This invention relates generally to clamping methods and apparatus. More particularly, the invention relates to clamping methods and apparatus for securing long rolls of paper (commonly referred to in the trade as "logs") during sawing processes.
Many types of paper are produced in logs for ease of manufacture. These logs must typically be sawn into shorter rolls more readily used by consumers and the like. Automating the sawing process is necessary to achieve satisfactory production rates. Typically, automated sawing processes have utilized a reciprocating or orbital radial or band saw in combination with a stationary log clamp.
Bias cutting and inadequate clamping of the log reduce the yield of prior art sawing processes. Tremendous pressure is placed on the saw blade as it cuts into the log because the saw blade is normally toothless to avoid shredding the log. Thus, this cutting process requires greater force to shear the log than a process involving a blade with teeth, increasing bias cutting and log core crushing problems.
Prior art clamps secure a log using elastic straps or grippers during the sawing process and may adjust for varying diameters. However, these clamps may allow slight movement during the sawing process, especially for logs of large diameter and heavy density. The clamp should stably hold the log when the blade applies large forces attempting to penetrate the paper. Therefore, a need exists for a clamping device which securely holds the log, helps the blade saw the log without bias cutting and adjusts for varying log diameters.